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Design and Discovery of New Piezoelectric Materials Using Density Functional Theory

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DESIGN AND DISCOVERY OF NEW PIEZOELECTRIC
MATERIALS USING DENSITY FUNCTIONAL
THEORY

by
Sukriti Manna

© Copyright by Sukriti Manna, 2018

All Rights Reserved
A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Mechanical Engineering).

Golden, Colorado Date

Signed:
Sukriti Manna

Signed:
Dr. Cristian V. Ciobanu
Thesis Advisor

Signed:
Dr. Vladan Stevanovi´c
Thesis Advisor

Golden, Colorado Date

Signed:
Dr. John Berger
Professor and Head
Department of Mechanical Engineering

ii
ABSTRACT
Piezoelectric materials find applications in microelectromechanical systems (MEMS), such as surface acoustic wave (SAW) resonators, radio frequency (RF) filters, resonators, and energy harvesters. Using density functional theory calculations, the present study illustrates the influence of alloying and co-alloying with different nitrides on piezoelectric and mechanical properties of an existing piezoelectric material such as aluminum nitride (AlN). Besides improving the performance of existing piezoelectric material, a high-throughput screening method is used to discover new piezoelectric materials.
AlN has several beneficial properties such as high temperature stability, low dielectric permittivity, high hardness, large stiffness constant, high sound velocity, and complementary metal-oxide-semiconductor (CMOS) compatibility. This makes it widely accepted material in RF and resonant devices. However, it remains a challenge to enhance the piezoelectric modulus of AlN. The first part of this thesis establishes that the piezoelectric modulus of AlN could be improved by alloying with rocksalt transition metal nitrides such as scandium nitride (ScN), yttrium nitride (YN), and chromium nitride (CrN). As the content of the rocksalt end member in the alloy increases, the accompanying structural frustration enables a greater piezoelectric response. This structural frustration is also accompanied by thermodynamic driving forces for phase separation which, with increased alloy concentration, lead to the destruction of the piezoelectric response upon transition to the (centrosymmetric, cubic) rocksalt structure. Thus, it becomes necessary to identify suitable alloying elements that may yield highest piezoelectric response with minimal alloying additions. The study reveals that the alloying with CrN would lead to the lowest transition composition (occurring at approximately 25% CrN concentration) between the wurtzite and rocksalt structures, thereby allowing piezoelectric enhancements at alloying levels that are easier to stabilize during the synthesis. The present study indicates that, for 25% CrN alloying, the piezoelectric modulus

iii is about 4 times larger than that of pure AlN. Thus, it is proposed to use CrxAl1−xN as a suitable replacement for AlN.
One of the adverse effect of transition metal nitride alloying for improvement of piezoelectric response is accompanied by the softening of AlN lattice. This would make the material less desirable for resonant applications. Our subsequent research establishes that co-alloying with YN and BN would enable the most superior combination of piezoelectric and mechanical properties of AlN.
The rest of the thesis describes our efforts for identifying new piezoelectric materials. This requires high-throughput screening of inorganic materials for their piezoelectric properties. Our quest to search for new piezoelectric compounds is motivated by the notion that soft materials have the opportunity to exhibit large piezoelectric response (piezoelectric modulus d), and the knowledge that the van der Waals (vdW) layered materials are typically soft in the layer stacking direction. From a pool of 869 vdW structures, we have discovered 50 new compounds such as In2Te5, GeTe, and CuVO3 having piezoelectric response larger than AlN. Remarkably, 70% of our discovered piezoelectric candidates do not contain any toxic elements like Pb. Our analysis reveals that the large components of d always couple with the deformations (shearing or axial) of van der Waals “gaps” between the layers. This research establishes a wide scope of synthesizing vdW materials for applications demanding high piezoelectric modulus.

iv
TABLE OF CONTENTS
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii LIST OF SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv LIST OF ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii DEDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix CHAPTER 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Piezoelectric Effect and Applications . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Classification of Piezoelectric Materials . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Vector/Tensor Quantities Related to Piezoelectricity . . . . . . . . . . . . . . . 4 1.4 Constitutive Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.5 Figures of Merit of Piezoelectric Devices . . . . . . . . . . . . . . . . . . . . . . 7
1.5.1 Figures of Merit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.5.2 Piezoelectric Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.6 Piezoelectric Materials: Present Status and Motivation for Computational
Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.6.1 Materials based on Single Crystal . . . . . . . . . . . . . . . . . . . . . 15 1.6.2 Materials Based on Polycrystalline Materials . . . . . . . . . . . . . . . 18 1.6.3 Toxicity of Lead-based Piezoelectrics . . . . . . . . . . . . . . . . . . . 23

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1.6.4 Motivation for Computational Research on Improving Piezoelectric
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1.6.5 Prior Computational Studies of Piezoelectric Properties . . . . . . . . . 25
1.7 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.7.1 Improving Performance of Existing Piezoelectric Materials . . . . . . . 27 1.7.2 Searching for New Piezoelectric Materials . . . . . . . . . . . . . . . . . 27
1.8 Organization of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
CHAPTER 2 ENHANCED PIEZOELECTRIC RESPONSE OF AlN via CrN
ALLOYING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.2.1 Paramagnetic Representation of Cr-AlN Alloys . . . . . . . . . . . . . . 34 2.2.2 Details of the DFT Calculations . . . . . . . . . . . . . . . . . . . . . . 34 2.2.3 Experimental Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.3.1 Enthalpy of Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.3.2 Piezoelectric Stress Coefficients . . . . . . . . . . . . . . . . . . . . . . 37 2.3.3 Comparison with Other Wurtzite-Based Alloys . . . . . . . . . . . . . . 42 2.3.4 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.4 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
CHAPTER 3 TUNING THE PIEZOELECTRIC AND MECHANICAL
PROPERTIES OF THE AlN SYSTEM VIA ALLOYING WITH YN AND BN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 3.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

vi
3.3 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
CHAPTER 4 LARGE PIEZOELECTRIC RESPONSE OF VAN DER WAALS
LAYERED SOLIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 4.2 Computational Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.2.1 Automated Identification of Quasi-2D Materials . . . . . . . . . . . . . 70 4.2.2 Calculating Piezoelectric Properties of Quasi-2D Materials . . . . . . . 71 4.2.3 Workflow for identifying quasi-2D piezoelectrics . . . . . . . . . . . . . 74
4.3 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.3.1 Promising Quasi-2D Piezoelectric Materials . . . . . . . . . . . . . . . 75 4.3.2 Role of van der Waals Interactions . . . . . . . . . . . . . . . . . . . . 80 4.3.3 Axial Piezoelectric and Elastic Anisotropy . . . . . . . . . . . . . . . . 82
4.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
CHAPTER 5 SUMMARY & CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . 86
5.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 5.2 Recommendations for Future Work . . . . . . . . . . . . . . . . . . . . . . . . 87
REFERENCES CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 APPENDIX A CLASSIFICATION OF PIEZOELECTRIC MATERIALS . . . . . . . 110 APPENDIX B DENSITY FUNCTIONAL THEORY METHODS . . . . . . . . . . . 112
B.1 Many-body Schr¨odinger equation . . . . . . . . . . . . . . . . . . . . . . . . 112 B.2 Density Functional Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
B.2.1 Hohenberg-Kohn Theorem . . . . . . . . . . . . . . . . . . . . . . . . 113

vii
B.2.2 The Kohn-Sham Equations . . . . . . . . . . . . . . . . . . . . . . . 114 B.2.3 Local Density Approximation . . . . . . . . . . . . . . . . . . . . . . 115 B.2.4 Generalized Gradient Approximation . . . . . . . . . . . . . . . . . . 116
B.3 Technical implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
APPENDIX C SIMULATING ELASTIC PROPERTIES . . . . . . . . . . . . . . . . 117 APPENDIX D MODELING OF RANDOM ALLOYS . . . . . . . . . . . . . . . . . 118
D.1 Details for Generating SQS Structures . . . . . . . . . . . . . . . . . . . . . 118 D.2 Dispersion of e33 and C33 values for different Y concentration . . . . . . . . . 119
APPENDIX E ADDITIONAL SUPPLEMENTARY INFORMATION OF
CHAPTER 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

E.1 Variations of e31 and C11 with Y and B composition . . . . . . . . . . . . . 121 E.2 Piezoelectric moduli as functions of composition . . . . . . . . . . . . . . . . 121
APPENDIX F SUPPLEMENTARY INFORMATION OF CHAPTER 4 . . . . . . . 124
F.1 Comparison of Experimental and Calculated Piezoelectric Modulus . . . . . 124 F.2 Axial Anisotropies: C vs e . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 F.3 Experimentally Measured Elastic Constants of Quasi-2D Materials . . . . . . 125 F.4 Schematics of Different Modes of d . . . . . . . . . . . . . . . . . . . . . . . 126 F.5 Rotation of d, e, and C-matrices . . . . . . . . . . . . . . . . . . . . . . . . 127
APPENDIX G PERMISSIONS FOR CONTENT REUSED . . . . . . . . . . . . . . 129

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LIST OF FIGURES
Figure 1.1 Schematics of direct piezoelectric effects: (a) at applied compressive stress, (b) at applied tension. (c) and (d) describe the schematics of converse piezoelectric effect at applied electric field. . . . . . . . . . . . . . 3

Figure 1.2 Classification of piezoelectric materials. They are classified into of piezoelectric, pyroelectric, and ferroelectric materials. . . . . . . . . . . . . 4

Figure 1.3 Correlation between different FOMs . . . . . . . . . . . . . . . . . . . . . 13 Figure 1.4 The advancement and milestones of piezoelectric single crystals . . . . . . 15 Figure 1.5 α-Quartz used as a piezoelectric oscillator in a watch . . . . . . . . . . . 17 Figure 2.1 Schematics of cation sublattice of CrxAl1−xN alloy. Al (Cr) sites are shown as gray (green) spheres. At a given Cr concentration, the Cr sites of each configuration have a different and random spin initialization with zero total spin in order to capture the paramagnetic state. . . . . . . 35

Figure 2.2 (a) DFT-calculated mixing enthalpies of the wurtzite and rocksalt phases of CrxAl1−xN as functions of Cr concentration. (b) Calculated mixing enthalpies for several wurzite-based nitride alloys grown experimentally. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 2.3 The 18 components of the piezoelectric tensor calculated for SQS supercells with different spin configurations and compositions of Cr. At each Cr composition, the open circles represent data for each SQS cell used, while the red solid circles represent the average values across the random initial configurations. . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 2.4 Variation of (a) et3o3tal, (b) e3cl3amped component of e33, (c) e3n3onclamped, (d)
33 component of the Born effective charge tensor, (e) strain sensitivity of internal parameter, (f) c/a ratio with respect to Cr addition. . . . . . . 40

Figure 2.5 (a) Variation of internal parameter, u with Cr addition. (b) Crystal structure of wurzite AlN. . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 2.6 Comparison of change in e33 with addition of different transition metals for x ≤ 25% regime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 2.7 Variation of (a) C33 and (b) d33 for several nitride-based wurtzite alloys. . 43

ix
Figure 2.8 Variation of e33 as function of Cr concentration for wurtzite phase alloys up to 50%. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Figure 2.9 Representative transmission electron microscopy (TEM) image (a) and an energy dispersive spectroscopy (EDS) line scan (b) of an (Al1−xCrx)N film cross section containing ∼7% Cr, confirming the incorporation of Cr into wurtzite solid solution. EDS data were collected along the dashed black line shown in panel (a). . . . . . . . . . . 47

Figure 2.10 X-ray diffraction patterns of the thin film combinatorial libraries plotted against the film composition, with comparison to the patterns for wurtzite (WZ) and rocksalt(RS) structures. For alloying content x < 30%, the films grow predominantly with the wurtzite structure. At higher Cr concentrations, x > 30%, both rocksalt and wurtzite phases are detected, and the wurtzite exhibits degraded texture. No films were produced with compositions in regions where no intensity is shown. . . . 48

Figure 3.1 Atomic structure of a representative SQS Al50Y25B25N alloy structure . . 54 Figure 3.2 [(a) and (b)] Lattice constants a and c for AlN-YN and AlN-BN alloys as a function of dopant (Y or B) cation concentration x. Panel (c) shows the c/a ratio for these alloys. . . . . . . . . . . . . . . . . . . . . . 55

Figure 3.3 Calculated mixing enthalpy curves for AlN alloyed with YN in the wurtzite (w) and rocksalt (rs) structures. . . . . . . . . . . . . . . . . . . 57

Figure 3.4 The design premise behind co-alloying AlN with YN and BN. (a)
Higher YN content in Al1−xYxN increases the piezoelectric coefficient e33 but decreases the elastic modulus C33. (b) Increasing concentration of BN in Al1−yByN has a small effect on the piezoelectric coefficient, but increases the elastic modulus. Thus, co-alloying with YN and BN could lead to increases in both piezoelectric coefficient and stiffness relative to pure AlN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Figure 3.5 Variation of piezoelectric coefficient in Al1−xYxN with strained applied along the a and c axes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Figure 3.6 The key piezoelectric (e33, red, left vertical axis) and elastic (C33, green, right axis) properties of Al-Y-B nitrides as functions of the Y concentration at constant boron levels ranging from (a) 0.00% B to (h) 43.75% B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figure 3.7 The coupling constants (a) k323 and (b) k321 as functions of the Y and B concentrations in Al1−x−yYxByN with at least 50% Al. . . . . . . . . . . . 63

x
Figure 4.1 Illustration of a quasi-2D material (TaSe2), showing the atomic structure of the layers and the van der Waals spacing between them. . . . 68

Figure 4.2 Correlation between experimentally measured longitudinal piezoelectric modulus (d33) and their elastic modulus (C33) . . . . . . . . . . . . . . . 69

Figure 4.3 Elastic constants of quasi-2D materials calculated with (a) GGA and
(b) vdW-corrected functional. The calculated values are compared with experimental ones. The calculations with the vdW-corrected functional are all within 50% error relative to the measurements. Details of measurement techniques, measurement temperatures, etc., are provided in the supplementary informations. . . . . . . . . . . . . . . . . . . . . . 72

Figure 4.4 Workflow for calculations of piezoelectric coefficient tensor eij, the elastic stiffness Cij, and the piezoelectric modulus tensor dij of quasi-2D materials. A vdW-corrected functional (optB86) is used in all calculations. We have calculated piezoelectric modulus of 80 quasi-2D materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 4.5 Left panel: plot of dmax = max(|dij|) against the space group number for 63 quasi-2D vdW materials with dmax > 0 (out of 135 non-centrosymmetric compounds). The two horizontal dotted lines denote the d33 values of PbTiO3 (119 pC/N) and AlN (5.5 pC/N). The blue square in this plot represents the hypothetical structure of PbS (distorted NiAs found in ICSD), not the ground rocksalt structure. Right panel: crystal structures of quasi-2D materials with large piezoelectric moduli. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 4.6 Histogram of the maximum components of (a) the piezoelectric coefficient tensor, emax and (b) piezoelectric modulus tensor, dmax. The most frequent emax is e33, whereas for dmax the most frequent maximum values are d15, d24 and d33. (c) Schematics of several important piezoelectric operating modes with their corresponding deformation types. The schematics of other relevant piezoelectric operating modes, i.e., components of dij are shown in the supplementary information. . . . 79

Figure 4.7 Correlation between axial anisotropy, i.e., out-of-plane to in-plane response ratio) of (a) d and e (b) d and C. The results reveal that majority of quasi-2D piezoelectric materials are dominated by out-of-plane piezoelectric responses (both in e and d) but elastically they are dominated in in-plane direction. . . . . . . . . . . . . . . . . . . 83

Figure A.1 Centrosymmetric and non-centrosymmetric (polar and non-polar) point groups. Only non-centrosymmetric point groups allow piezoelectricity. . 110

xi
Figure D.1 Calculated e33 and C33, for each individual SQS and averaged, at each concentration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Figure E.1 Piezoelectric coefficient e31 and elastic modulus C11 as functions of Y and B concentrations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

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    2017 Minerals Yearbook LITHIUM [ADVANCE RELEASE] U.S. Department of the Interior September 2020 U.S. Geological Survey Lithium By Brian W. Jaskula Domestic survey data and tables were prepared by Annie Hwang, statistical assistant. In the United States, one lithium brine operation with an cobalt oxide and 2,160 kg of lithium-nickel-cobalt-aluminum associated lithium carbonate plant operated in Silver Peak, oxide (Defense Logistics Agency Strategic Materials, 2017). At NV. Domestic and imported lithium carbonate, lithium yearend 2017, the NDS held 540 kg of lithium-cobalt oxide and chloride, and lithium hydroxide were consumed directly 1,620 kg of lithium-nickel-cobalt-aluminum oxide. in industrial applications and used as raw materials for downstream lithium compounds. In 2017, lithium consumption Production in the United States was estimated to be equivalent to The U.S. Geological Survey (USGS) collected domestic 3,000 metric tons (t) of elemental lithium (table 1) [16,000 t production data for lithium from a voluntary canvass of the of lithium carbonate equivalent (LCE)], primarily owing to only U.S. lithium carbonate producer, Rockwood Lithium Inc. demand for lithium-based battery, ceramic and glass, grease, (a subsidiary of Albemarle Corp. of Charlotte, NC). Production pharmaceutical, and polymer products. In 2017, the gross weight and stock data collected from Rockwood Lithium were withheld of lithium compounds imported into the United States increased from publication to avoid disclosing company proprietary data. by 7% and the gross weight of exports increased by 29% from The company’s 6,000-metric-ton-per-year (t/yr) Silver Peak those in 2016.
  • Kalenga Tite Mwepu a Dissertation Submitted in Partial Fulfillment of The

    Kalenga Tite Mwepu a Dissertation Submitted in Partial Fulfillment of The

    LITHIUM EXTRACTION FROM ZIMBABWEAN PETALITE WITH AMMONIUM BIFLUORIDE DIGESTION Kalenga Tite Mwepu A dissertation submitted in partial fulfillment of the requirements for the degree Master of Science in Applied Science (Chemical Technology) in the Department of Chemical Engineering, Faculty of Engineering, Built Environment and Information Technology. Supervisor: Prof. Philip Crouse Co-supervisor: Dr Salmon Lubbe February 2020 Declaration I, Kalenga Tite Mwepu, student No. 15261043, do hereby declare that this research is my original work and that it has not previously, in its entirety or in part, been submitted and is not currently being submitted, either in whole or in part, at any other university for a degree or diploma, and that all references are acknowledged. SIGNED on this ________________________ day of_____12/02______________ 2020. __________________ Kalenga Tite Mwepu ii Synopsis Lithium carbonate is the precursor for most other lithium compounds. The market demand for lithium is increasing because it is used for many applications such as the preparation of electrode material and electrolyte for lithium-ion batteries, for treatment of manic depression, production of electronic grade crystals of lithium niobate and tantalite, and preparation of battery-grade lithium metal. Previously reported methods of lithium extraction require high temperature calcination for phase transformation from α-spodumene into β-spodumene, that is energy consuming and costly. This step is required because of the higher chemical reactivity of β-spodumene. The objectives of this research were to investigate the viability of ammonium bifluoride digestion of the petalite concentrate from the Bikita deposits without the initial thermal conversion to β- spodumene, in order to produce a high purity lithium carbonate in a cost efficient way, and optimising the remaining process parameters of the full process.
  • Chen Mines 0052E 11348.Pdf

    Chen Mines 0052E 11348.Pdf

    UNDERSTANDING STRUCTURE-PROPERTY RELATIONS IN -EUCRYPTITE UNDER PRESSURE AND AT ELEVATED TEMPERATURE by Yachao Chen A thesis submitted to the faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Materials Science) Golden, Colorado Date: _______________________ Signed: _______________________ Yachao Chen Signed: _______________________ Dr. Ivar E. Reimanis Thesis Advisor Golden, Colorado Date: _______________________ Signed: _______________________ Dr. Angus Rockett Professor and Department Head Department of Metallurgical and Materials Engineering ii ABSTRACT -eucryptite (LiAlSiO4) has received widespread attention from both industry and academia due to its negative coefficient of thermal expansion (CTE) and one-dimensional Li ionic conductivity. Additionally, -eucryptite undergoes a pressure-induced phase transformation at relatively low pressures. These various behaviors arise because the crystal structure is open and highly anisotropic. The present study uses several experimental methods to better understand the relation between the structure and the electrical and mechanical behavior of -eucryptite. Synthesis and processing methods were developed to make pure -eucryptite and - eucryptite doped with Mg of varying particle sizes. In-situ diamond anvil cell - x-ray diffraction was performed to study the pressure induced phase transformation from -eucryptite to the high pressure phase -eucrypite. With the assistance of Rietveld refinement and atomistic modeling, the crystal structure of the -eucrypite was determined to be an orthorhombic with space group Pna21. This is the first time that both space group and atomic positions of the high pressure phase have been reported. It is also observed that Mg-doped -eucryptite undergoes the pressure induced transformation at slightly higher pressures than pure -eucryptite (2.47 GPa compared with 1.8 GPa hydrostatic stress), implying that Mg stabilizes -eucryptite.
  • A Review of Rare-Element (Li-Cs-Ta) Pegmatite Exploration Techniques for the Superior Province, Canada, and Large Worldwide Tantalum Deposits

    A Review of Rare-Element (Li-Cs-Ta) Pegmatite Exploration Techniques for the Superior Province, Canada, and Large Worldwide Tantalum Deposits

    Exploration and Mining Geology, Vol. 14, Nos. 1-4, pp. 1-30, 2005 © 2006 Canadian Institute of Mining, Metallurgy and Petroleum. All rights reserved. Printed in Canada. 0964-1823/00 $17.00 + .00 A Review of Rare-Element (Li-Cs-Ta) Pegmatite Exploration Techniques for the Superior Province, Canada, and Large Worldwide Tantalum Deposits JULIE B. SELWAY, FREDERICK W. BREAKS Precambrian Geoscience Section, Ontario Geological Survey 933 Ramsey Lake Road, Sudbury, ON P3E 6B5 ANDREW G. TINDLE Department of Earch Sciences, Open University Milton Keynes, Buckinghamshire, UK MK7 6AA (Received February 16, 2004; accepted September 20, 2004) Abstract — Rare-element pegmatites may host several economic commodities, such as tantalum (Ta- oxide minerals), tin (cassiterite), lithium (ceramic-grade spodumene and petalite), and cesium (pollucite). Key geological features that are common to pegmatites in the Superior province of Ontario and Manitoba, Canada, and in other large tantalum deposits worldwide, can be used in exploration. An exploration project for rare-element pegmatites should begin with an examination of a regional geology map. Rare-element pegmatites occur along large regional-scale faults in greenschist and amphibolite facies metamorphic terranes. They are typically hosted by mafic metavolcanic or metasedimentary rocks, and are located near peraluminous granite plutons (A/CNK > 1.0). Once a peraluminous granite pluton has been identified, then the next step is to determine if the pluton is barren or fertile. Fertile granites have elevated rare element contents, Mg/Li ratio < 10, and Nb/Ta ratio < 8. They commonly contain blocky K-feldspar and green muscovite. Key fractionation indicators can be plotted on a map of the fertile granite pluton to determine the fractionation direction: presence of tourmaline, beryl, and ferrocolumbite; Mn content in garnet; Rb content in bulk K-feldspar; and Mg/Li and Nb/Ta ratios in bulk granite samples.
  • Develop and Characterization of Transparent Glass Matrix Composites

    Develop and Characterization of Transparent Glass Matrix Composites

    DEVELOPMENT AND CHARACTERIZATION OF TRANSPARENT GLASS MATRIX COMPOSITES Bo Pang A thesis submitted in fulfilment of the requirements of the degree of Doctor of Philosophy Imperial College London Department of Materials LONDON, 2011 Preface This thesis describes research carried out by the author in the Department of Materials of Imperial College during the period from January 2008 to January 2010, under the supervision of Dr. David McPhail and Prof. Aldo R. Boccaccini. No part of this work has been accepted or is being currently submitted for any other qualification in this college or elsewhere. Some of the results presented in this thesis have been published and presented in various journals and conferences. Journal publications B. Pang, D. McPhail, D.D. Jayaseelan, and A.R. Boccaccini, Development and Characterization of Transparent Glass Matrix Composites. Advances in Science and Technology, 2011. 71: p. 102-107. B. Pang, D. McPhail and A.R. Boccaccini, Glass Matrix Composites for Transparent Security Measures. Materials World, February 2011: p.20-22. Conference contributions Development and characterisation of transparent glass matrix composite. B. Pang, D. McPhail and A.R. Boccaccini. Oral presentation at the Annual Meeting of Society of Glass Technology, Murray Edwards College, Cambridge, UK. 6-10 September 2010. Development and characterisation of transparent glass matrix composite. B. Pang, D. McPhail and A.R. Boccaccini. Oral presentation at CIMTEC 2010 - 12th International Ceramics Congress, Montecatini Terme, Italy. 6-11 June 2010. 1 Abstract Glass matrix composites based on NextelTM alumina fibre reinforced borosilicate glass have been fabricated to improve their mechanical property and fracture toughness. In this work, a novel processing technique, which is called “sandwich” hot-pressing, has been used.
  • First Principles Study on the Formation of Yttrium Nitride in Cubic and Hexagonal Phases

    First Principles Study on the Formation of Yttrium Nitride in Cubic and Hexagonal Phases

    Manuscript including Title Page & Abstract First Principles Study on the Formation of Yttrium Nitride in Cubic and Hexagonal Phases G. Soto, M.G. Moreno-Armenta and A. Reyes-Serrato Centro de Ciencias de la Materia Condensada, Universidad Nacional Autónoma de México, Apartado Postal 356, Ensenada, Baja California. CP 22800, México. Abstract We have studied the formation of yttrium nitride in which the Y-atoms were arranged in two common close-packed stacking: The AB-stacking (hcp-symmetry) is the ground state of metallic yttrium; while the ABC-stacking (fcc-symmetry) is the ground state of yttrium nitride. Given the different symmetries between YN and Y, there must be a phase transition (hcp → fcc) as N is incorporated in the Y-lattice. By means of first principles calculations we have made a systematical investigation where N was gradually incorporated in octahedral interstices in AB and ABC stacking of Y. We report the heat of formation, bulk modulus, lattice parameter and electronic structure of the resultant nitrides. We found that both metal arrangements are physically achievable. Furthermore, for low nitrogen incorporation the two phases may coexist. However for high nitrogen concentration the cubic phases are favored by a 30 kJ mol-1 margi n. These results are important since fcc-YN is semiconducting and could be utilized as active layer in electronic devices. PACS: 71.15.Nc; 71.20.-b; 71.20.Be; 71.20.Lp; 71.20.Nr; 72.80.Ga Keywords: Yttrium nitride; Interstitial alloys; Transition metal nitrides; Ab initio; DFT; LAPW 1 Introduction The Transition (T) Metal (M) Nitrides (N) are valuable for several technological applications.
  • Lithium Resources and Requirements by the Year 2000

    Lithium Resources and Requirements by the Year 2000

    Lithium Resources and Requirements by the Year 2000 GEOLOGICAL SURVEY PROFESSIONAL PAPER 1005 Lithium Resources and Requirements by the Year 2000 JAMES D. VINE, Editor GEOLOGICAL SURVEY PROFESSIONAL PAPER 1005 A collection of papers presented at a symposium held in Golden, Colorado, January 22-24, 1976 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director First printing 1976 Second printing 1977 Library of Congress Cataloging in Publication Data Vine, James David, 1921- Lithium resources and requirements by the year 2000. (Geological Survey Professional Paper 1005) 1. Lithium ores-United States-Congresses. 2. Lithium-Congresses. I. Vine, James David, 1921- II. Title. HI. Series: United States Geological Survey Professional Paper 1005. TN490.L5L57 553'.499 76-608206 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-02887-5 CONTENTS Page 1. Introduction, by James D. Vine, U.S. Geological Survey, Denver, Colo ______________-_______-_-- — ------- —— —— ——— ---- 1 2. Battery research sponsored by the U.S. Energy Research and Development Administration, by Albert Landgrebe, Energy Research and De­ velopment Administration, Washington, D.C., and Paul A. Nelson, Argonne National Laboratory, Argonne, Ill-__- —— -____.—————— 2 3. Battery systems for load-leveling and electric-vehicle application, near-term and advanced technology (abstract), by N. P. Yao and W. J. Walsh, Argonne National Laboratory, Argonne, 111___.__________________________________-___-_________ — ________ 5 4. Lithium requirements for high-energy lithium-aluminum/iron-sulfide batteries for load-leveling and electric-vehicle applications, by A.
  • Mineralogy and Geochemical Evolution of the Little Three

    Mineralogy and Geochemical Evolution of the Little Three

    American Mineralogist, Volume 71, pages 406427, 1986 Mineralogy and geochemicalevolution of the Little Three pegmatite-aplite layered intrusive, Ramona,California L. A. SrnnN,t G. E. BnowN, Jn., D. K. Brno, R. H. J*rNs2 Department of Geology, Stanford University, Stanford, California 94305 E. E. Foono Branch of Central Mineral Resources,U.S. Geological Survey, Denver, Colorado 80225 J. E. Snrcr,nv ResearchDepartment, Gemological Institute of America, 1660 Stewart Street,Santa Monica, California 90404 L. B. Sp.c,uLDrNG" JR. P.O. Box 807, Ramona,California 92065 AssrRAcr Severallayered pegmatite-aplite intrusives exposedat the Little Three mine, Ramona, California, U.S.A., display closelyassociated fine-grained to giant-texturedmineral assem- blageswhich are believed to have co-evolved from a hydrous aluminosilicate residual melt with an exsolved supercriticalvapor phase.The asymmetrically zoned intrusive known as the Little Three main dike consists of a basal sodic aplite with overlying quartz-albite- perthite pegmatite and quartz-perthite graphic pegmatite. Muscovite, spessartine,and schorl are subordinate but stable phasesdistributed through both the aplitic footwall and peg- matitic hanging wall. Although the bulk composition of the intrusive lies near the haplo- granite minimum, centrally located pockets concentratethe rarer alkalis (Li, Rb, Cs) and metals (Mn, Nb, Ta, Bi, Ti) of the system, and commonly host a giant-textured suite of minerals including quartz, alkali feldspars, muscovite or F-rich lepidolite, moderately F-rich topaz, and Mn-rich elbaite. Less commonly, pockets contain apatite, microlite- uranmicrolite, and stibio-bismuto-columbite-tantalite.Several ofthe largerand more richly mineralized pockets of the intrusive, which yield particularly high concentrationsof F, B, and Li within the pocket-mineral assemblages,display a marked internal mineral segre- gation and major alkali partitioning which is curiously inconsistent with the overall alkali partitioning of the system.
  • Silicate Mineral Eutectics with Special Reference to Lithium

    Silicate Mineral Eutectics with Special Reference to Lithium

    materials Article Silicate Mineral Eutectics with Special Reference to Lithium Agata Stempkowska Department of Environmental Engineering, Faculty of Civil Engineering and Resource Management, AGH University of Science and Technology, Mickiewicza 30 Av., 30-059 Cracow, Poland; [email protected] Abstract: In this paper, the system of natural mineral alkali fluxes used in typical mineral industry technologies was analyzed. The main objective was to reduce the melting temperature of the flux systems. Particular attention was paid to the properties of lithium aluminium silicates in terms of simplifying and accelerating the heat treatment process. In this area, an alkaline flux system involving lithium was analyzed. A basic flux system based on sodium potassium lithium aluminosilicates was analyzed; using naturally occurring raw materials such as spodumene, albite and orthoclase, an attempt was made to obtain the eutectic with the lowest melting point. Studies have shown that there are two eutectics in these systems, with about 30% spodumene content. The active influence of sodium feldspar was found. Keywords: Li-Na-K flux system; mineral eutectic; spodumene 1. Introduction 1.1. Characteristics of Flux Minerals Lithium is a very common yet dispersed element. The largest resources are found in Citation: Stempkowska, A. Silicate seawater—billions of tons of highly diluted lithium (the range is from 0.001 to 0.020 mg/L Mineral Eutectics with Special lithium), which cannot be extracted on an industrial scale [1,2]. In dissolved form, lithium Reference to Lithium. Materials 2021, has only positive effects on supplementation of its deficiencies in humans [3,4]. Minerals 14, 4334. https://doi.org/10.3390/ containing lithium in nature are formed from the transformation of pegmatites.